pgmabel [-help] [-axis axis] [-factor factor] [-pixsize pixsize] [-left | -right] [-verbose] [filespec]
This program is part of Netpbm(1).
pgmabel reads as input a PGM image, which it assumes to be an image of a rotational symmetric transparent object. The image must have a vertical symmetry axis. pgmabel produces as output an image of a cross-section of the image.
pgmabel does the calculation by performing the Abel Integration for Deconvolution of an axial-symmetrical image by solving the system of linear equations.
After integration, pgmabel weights all gray-values of one side by the surface area of the calculated ring in square pixels divided by 4*factor multiplied by the size of one pixel (pixsize). With the -verbose option, pgmabel prints the weighting factors.
Where the calculation generates a negative result, the output is black.
The computation is unstable against periodic structures with size 2 in the vertical direction.
You can abbreviate any option to its shortest unique prefix.
Rotate a PGM image to get an image with a vertical axis of symmetry, then calculate the cross section:
pnmrotate 90 file.pgm | pgmabel -axis 140 >cross_section.pgm
This program was added to Netpbm in Release 10.3 (June 2002).
Volker Schmidt (email@example.com)